The continuing use of electronic equipment has been attended by problems caused by electro magnetic interference (EMI) and electro static discharge (ESD); EMI resulting in interference with proper signal transfer and ESD destroying electronic components through excessive voltage. An answer to these problems has been generally one of providing filtering to filter out the unwanted frequency components represented by EMI and to provide voltage protection to preclude voltage spikes or surges from getting through to cause a circuit component damage. A widely used practice has been to place discrete filters on circuit boards selected to block those frequencies that may interfere with signals, particularly digital signals or the components and harmonics of such signals and to utilize voltage surge devices, additionally board mounted, to provide surge protection. U.S. Pat. No. 4,729,752 describes a connector having a built in signal transient suppressor that may be utilized with existing connectors to provide a compact solution to the problem and save expensive printed circuit board space. Signal voltage transient suppression is provided in a preferred embodiment by bi-directional diode, or diodes to provide protection for both positive and negative voltage surges. One embodiment of the device teaches the use of filtering means in the form of filter sleeves of a type illustrated in U.S. Pat. No. Re. No. 29,258 in combination with the transient protection; and both fitted within the housing of a multi-pin connector.
The foregoing solution to the problem of filtering unwanted components of signals and protecting against voltage surges involves the use of discrete filter and voltage protector components requiring an assembly entailing the individual handling of small electronic devices, multiple steps and soldering operations and while of considerable utility entail a cost limiting use to those applications where surge protection and filtering functions are more important than cost. As a result, numerous applications involving particularly consumer electronic devices, vehicular electronic circuits and the like have not been protected.
Accordingly, it is an object of the present invention to provide an improved, low cost filter/surge protector device that readily lends itself for assembly into connectors and the like.
It is a further object to provide an integrated filter/surge protector that may be used with existing connectors as a retrofit or utilized in the ever increasing applications that require an economic solution to EMI and ESD phenomenon.
It is yet a further object to provide a connector insert that includes an LC network and voltage protection in an integral structure that can be manufactured as such, handled, installed into connectors to provide such functional protection.
It is a final object of the invention to provide a novel connector combination having built-in filtering and voltage protection.